There is a pumping-ejector unit, comprising a pump, a separator and a jet apparatus, wherein the water, fed into the jet apparatus by the pump, falls down by gravity and thus entrains into the apparatus the air being compressed. Then the air is separated from the water in the separator. The compressed air from the separator is delivered to consumers and the water is fed back into the jet apparatus by the pump (see SU patent, 1955, MPK 6 F04 F 5/12, Nov. 30, 1926).
Significant imperfection of this compression unit is dependence of the unit's effectiveness on the jet apparatus' height, that results in significant increase of unit's dimensions and in high specific material consumption during its manufacture.
The closest analogue of the unit, described in the invention, in its technical essence and in the achieved result is a pumping-ejector unit, comprising a pump, a separator and a liquid-gas ejector, wherein the liquid-gas ejector is connected through its gas inlet to a source of evacuated medium, through its outlet--to the separator, discharge side of the pump is connected to the ejector's nozzle (see, Lyamaev B. F., "Hydro-jet pumps and units" book, Leningrad, "Mashinostroenie", 1988, pages 139-141).
This compression unit can be used for evacuation and compression of various gaseous mediums. However, efficiency factor of such units is relatively low due to high required power input.